Signors to said donaijj mt



Dec. 29, 1931. G. NAISMITH'ET AL FURNACE 2 Sheets-Sheet Original Filed Dec. 12. 1927 WBW I INVENTQRS.

w ATTORNEY G. NAISMITH ET AL R 18,303

FURNACE Original Filed Dad 12. 1927 2 sh s 2 MN hm mm INVENTORS.

BY MJLJM.

4% A'TTORNEY.

M \W u Dec. 29, 1931.

mm W NW Q, N m N;

Reissued Dec. 29; 1931 UNITED VSTATESF'PATENT OFFICE] GEORGE NAISMITH Aim DONALD M. NAISMITH, OFYPITT'SBUBJGH, PENNSYLVANIA, AS- I sIGNoRs'ro sun DONALD m. musm'rn r FURNACE driginal No. 1,732,137, dated October 15, 1929, Serial 1%. 239,322,fi1ed December 12, 1927. Application for reissue flled February 2, 1931. Serial No. 513,030. v

Our invention is an improvement in heating furnaces of the regenerative type particularly adapted to the heating of ingots and the like. The furnace embodies a main heating chamber and a supplemental pre-heat ing or preliminary heating chamber, adapted to be maintained in open communication with the main heating chamber with partial circulation of combustion-gases therethrough, or di- Vided from the main heating chamber and having a supplemental fuel supply. f The invention has in view to provide a regenerative furnace'construction in which the fuel gases pass through pre-heating checkerwork arranged below air pie-heating checker-- work with circulation through the main heating chamber of the furnace, and return of the gases of combustion through correspondingly arranged checkerwork at the other side of a partition wall with circulating ports, reversing valves, etc., as shall be more fully hereinafter described.

Also, to provide for partial circulation of a portion of the main gases of combustion through the pre-heating furnace chamber with return of the waste gases to the stack without circulation through the checkerwork and independent thereof, but utilizing refracted heat therefrom, or withdrawal of the products of combustion from such independ ent fuel supply in the same manner. The main heating chamber or soaking pit, when in communication with the pre-heating furnace chamber, or cut off therefrom, receives the incoming pre-heated fuel gas and air in combustion at one side of the main chamber and discharges a part or all of the waste gases at the other side of the main furnace chamber, through whichthe gases circulate in an approximately horizontal or horseshoe-shaped path, alternating with each reversal of the valves, whereby the ingots etc. are exposed to the heating action at all times.

The invention also utilizes a supplemental air supply for furnishing additional air to the air pro-heating checkerwork for supplementing the heated air supply, under certain conditions of operation.

In the drawings showing preferred embodiments of the invention:

Fig. 1 is a longitudinal vertical section through the furnace on theline I'I of Fig. 2;

Fig. 2 is a horizontal section, partly in plan, on thesection line IIII of Fi 1, showing the air pre-heating checkerwor in Fig. 3 is alongitudinal sectional view on the line III-III of Fig. 4, showing the independent waste gas return circulation from the pre-heating furnace, to the stack;

Fig. 4 is a horizontal sectional view on the line IVIV"of Fig. 3; i

Fig. 5 is a vertical cross sectional view on the lineV-'V of Fig. 4:;

Fig.6 isa partial horizontal sectional view similar to the heating furnace .construction of Fig. 2, but showing the pre-heatinlg furnace closed off from themain heating'furnace and provided with an independent. fuelsup- P y-- I The main soaking it or heating chamber 2 of the furnace is of generally rectangular construction within sidewalls 3- 3, an outer end wall 4 and in'n'er'transverse partition 5. The latter forms a partial closure of the heating chamber 2, forming the inner 'end' portion of the regenerative part of the furnace, which is also enclosed between the main side walls 3 and the opposite end'wall 4.

In the principal construction an end wall 6. is not continuous across the end of main heating chamber 2,'but is provided with a middle opening'leading into the supplemental or pre-heating chamber 2a enclosed within the supplemental side walls 3a and an endmost closing wall 6a. '3

A central double-sided artition wall or pier 7 extends vertically rom the base of the constructionupwardly'to the roof forming a support for the arched coverings 88 of the upper side-by-side airregenerative chambers A and longitudinally from partition 5 to end wall 4. Chamber A is arranged vertically above gas regenerative chamber B, both chambers being preferably of equal width and in duplicate arrangement at opposite sides of the hollow pier 7 between the main end wall 4 and an opposite inner wall 9 Wall 9 extends'from the base upwardly 'to the top of the checkerwork in chamber A,

' leaving an intervening horizontal space for described.

circulation of gaseseither from or to the checkerwork below the roof arches 8.

Between Walls 9 and 5 and at each side of hollowpier Zis a vertical portll communicating with the upper portion of chamber B by port 12, and upwardly extending port 11 carries heated gas for mixture with heated air in the common mixing, combustion and delivery channel 13.

chambers A and B and leads into themain furnace chamber2 at one .Sidewith, a correis reversed upon reversal of the valves, accordingto the well known principle of-operation of regenerative furnaces of the Siemens valve type.,

As indicated, Figs. 1 and 2, a portionof the gases 1 of; combustion Jpass outwardly through -pre-hea ting.. ,chamber 2a,...the constructionof which andmeans for conducting the waste gases to the stack will be hereafter As shown, the opposite inner surfaces of main side walls 3 are continuous,'avoiding any abutment or shoulder projections, and

facilitating-circulation of the gase's'to and from the; main furnace chamber and with circulation'therein in a horeshoe-shaped path around and between the ingots,1as in Fig. 2. The furnacecchamber 2 is provided with a suitable receiving and supporting floor 14, carried outwardly beyond the mains-wall 5 throughout the extent of: both, the main and supplemental: chambers,-be'yond main wall 5, on a structuraksupporting platform 15, with suitable reinforcing ibuckstaves, etc, as; is usualein such construction. V g 1 A removable cover 16 provided with supporting.- wheels 17 is, adapted to be moved along a supporting trackway for opening and closingthe main furnace. cha1nbe'r2, similar covers 160 being provided-forf-the supplemental pre-heating chamber 20, for opening and closing one or both ofsaid chambers, as

inZFig. 1.:

'"Any slag or other accumulation in the bottom portion 18 of port 11 may beremoved through an opening 19at the base of wall 5, having a suitable cover or door'20;

The checkerwork in chamber "A extends upwardly above supporting walls 21 with in ter'vening circulation. passages 22 communieating with the port 23 at each side of-the middle hollow pier or wall portion of the valve suppoitingstructure 24 and with? the revers air circulation-controlling valve/G; *By

this arrangement, the incoming air circulates vertically upward. through'the cheCkerwbrk A throughout itsfull extent. The operation of s'aiid'valve Gwillibe readunderstood by those familiar with the art,-

supplying air alternately to one or the other of the air regenerative chambers A and with return of the waste gases from the other chamber to the outlet opening 25, leading to the stack.

The checkerwork in chamber B is suitably arranged, providing a comparatively deep body of closely assembled alternating series ofvertic'all-y arranged tiles or bricks for very a 5 complete" and thorough contact therewith of Each of'such channels is of substantially the same width as that of the checkerwork'" the incoming gas for heating.

The gas supply entering the furnace I through. valve YD passes from the v valve 7 I v 1 through a conduit or port26 inwardly to spending return channel 13 at the opposite side, as in Fig. 2. Obviously, the circulation feet of the stack draft on the outgoing flue gases in the gas pre-heating checkerwork in chamber B maybe accurately regulated and controlled in operating the furnace,

The supplemental or pre-heating chamber 2a is provided at its, outer end with a port or flue extension 29 extending through the upper portion of end wall or column 6a. V

; A downwardly extending flue30 connects with ahorizontalv flue 31, under the middle portion of the foundation and having an upwardly and outwardly leading flue extension or conduit 32, communicatingwith the stack and with themain products of combustion from conduits 25 and 28 from valves C and D. I ,Flue 30 is provided at its upper end with an opening and closing valve 33 having an operating rod 3&, by which circulation of gases through the supplemental chamber2a may be regulated. r I

Exhaust flue or port 30 preferably leads from near the bottomof supplemental portion 2a of the soaking pit 2 so that when valve 83is open a portion of the heating gases is diverted'therefrom by means of such exhaust flue or port, 1

For the purpose of-adding supplemental air to theupper chambers A, the middle wall or pier 7 is hollow as shown, and provided with longitudinal air cavities 35 separated by a middlelongitudinal partition 36 and closed at the. top by covers 37.

' Each of said chambers 35 communicates at the bottom by ports 38 and inner longitudinal V openings 22 with the main checkerwork chamber. Air supply connections 39 leading from any suitable source and provided with proper regulating valves are arranged to introduce supplemental air to the cavities 35,

so as to amplify the air supply when desired, with pre-heating, and combination 5 with the main mixture in the circulation.

By such means the operation of the furnace can be speeded up under certain conditions and as desired, within the control of the operator.

When desired the supplemental pre-heating chambr 2a may be blocked off from the main chamber 2 by a transverse partition 10, as shown in Fig. 6. In such case the supplemental chamber is provided with independent fuel and air supply, as gas or oil, by series of pipes i1 leading inwardly through the opposite side walls 3a, as in Fig. 6. Otherwise, the construction and operation is the same as above described.

In either case, whether the main and supplemental furnace chambers are in communication, or independent, the ingots etc. to be heated may be first placed in the pre-heating chamber 2a and after pre-heating by either of the methods described are then lifted out and placed in the main chamber 2, with manipulation of the covers 16 and 16a, where they are subjected to the full heating action of the furnace.

The main and supplemental chambers 2 and 2a may however, be used together as one continuous heating chamber, under continued operation of the furnace with proper control, without necessary pre-heating.

What we claim is:

1. A regenerative heating furnace provided with a middle hollow ported wall, continuous side walls enclosing inner regenerative chambers and a main heating chamber forming an extension thereof beyond the middle wall, said chamber having a pre-heating extension, and -means providing a circulation of heating gases from the regenerative chambers through the main heating chamber across the end of the middle wall and return therefrom to companion regenerative chambers with passage of a portion gf the gases through the pre-heating cham- 2. A regenerative heating furnace provided with a middle hollow ported wall, continuous side walls enclosing inner regenerative chambers and a main heating chamber forming an extension thereof beyond the middle wall between the opposite side walls, alternately operative pre-heating regenera tive chambers for gas and air between said walls communicating directly between the side walls with the heating chamber for circulation therethrough, a supplemental preheating chamber forming an extension of the main heating chamber, and an outgoing flue for products of combustion communicating with the other end of the pre-heating chamber.

3. A regenerative heating furnace provided. with, continuous side walls enclosing inner regenerative chambers and a main heat ing chamber forming an extension thereof between its opposite side walls forming extensionsofsaid'walls, alternately operative pre heating regenerative chambers between said walls and amiddle wall, said regenerative chambers opening into the inner end of the heating chamber for supply at one side' and exhaust at the other, each of. said regenerative chambers having an upper air regenerative portion anda lower gas'regene'rative portion, and a pre-heating furnace forming a reduced extensioniof the main heating furnace provided at its opposite end with a take-off flue for products of combustion.-

4. A regenerative heating furnace pro- I vided with continuous side walls enclosing inner regenerative chambers and a'main heating chamber forming an extension thereof between its opposite side walls forming extensions of said walls, alternately operative preheating regenerative chambers between said walls and a middle wall, said-regenerative chambers opening into theinner end of the heating chamber for supply at one side and exhaust at the other, each of said regenerative chambers having an upper air regenerative portion and a lower gas regenerative portion, means for. supplying air through the middle Wall to the air pre-heating chamber, and a pre-heating furnace forming a reduced extension ofthe main heating furnace provided at its opposite end with a take-off flue for products of combustion. h I

5. A. regenerative heating furnace provided with continuous side walls enclosing inner regenerative chambers and a main heating chamber forming an extension thereof between its opposite side walls forming extensions of said walls, alternately o erative pre-heating regenerative chambers etween said walls and a middle wall, said regenera- 1 tive chambers opening into the inner end of the heating chamber for supply at one side and exhaust at the other, each of said regenerative chambers having an upper air regenerative portion and a lower gas regenerative portion, a pre-heating furnace forming a reduced extension of the main heating furnace provided at its opposite end with a take-01f flue for products of combustion, and valve controlled conduits for supplying gas and air to the lower and upper regenerative chambers at one side of the middle wall and for withdrawing products of combustion from the other side of said wall for circulation to a take-off flue or stack.

6. In a furnace of the class described, a main heating chamber extending across between opposite continuous straight side walls having a middle reduced pre-heating extension, regenerative gas and air chambers at 4 o i v mans each sidebetweenthe continuous straight mills; into the main heating chambe n ehosflow middle wall having. circulating ports communicating with the regenerative chambers and'terminating at the main heat.- in'g chamber, means providing alternating suppky'xmd return. circulation :through said regenerative gas and air ehambers having eonnectiorr with a steck-flue, and:a flue eenneet'edi with the outer end of the-spreheating chinnber and. with the stack flue.-

:combina.tion a soaking" pit, means for admitting a combustiblemixture at one side thereof: and projecting the resulting 1:5 gaseous stream across the soazhng. pit to the opposite side thereof, said pit having one or more: exhaustv passages for the, heating gases near the same side thereof which cause a portion of said stream to returnacross the pit in a horseshoe-shaped path and pass out oiithe pit through said passages, and one or more; auxiliary exhaust ports located adja cent the "(opposite side of the pit. which divert a-portimna of said gaseous stream-fromisaid 5 horseshoe-shapedlpath; 'f I I 8 Inconibinationfa soaking-pit, means for-admittinga combustible mixture'at one side thereof and projecting-the resulting gaseous stream across the. soaking pit to the 39 oppesite side thereof," said spit having one or more exhaust paissages for the heating gases near the sameside thereof which cause a portion of saisdstream to return across the pit in ahorseshoe sha'ped path and pass out 3' of the pit through said passages, one or-more aruxiliery exhaust; ports located adjacent the opposite side of the pit which divert exportion of said gaseousstream froln'said horseshoe shaped path; and means 'forregulating .5 the proportion of gases flowing through said passages and ports;

In testimony whereof wehereunto aflix our sig atures l I 'GEORGE'NAISMITH; I

I DQNALIJ M. NAISMITH.

is so 

